Thrust bearing bulkhead in a transmission of a motor vehicle

Abstract

The present invention relates to a transmission for an automotive vehicle having a clutch retainer assembly or thrust bulkhead fixedly secured to the transmission housing and interdisposed between the reverse clutch assembly and the fourth clutch assembly. A pair of thrust bearing assemblies are interdisposed between the clutch assemblies and the thrust bulkhead to transfer the axial thrust loads generated by the multiple planetary gear assemblies through the thrust bulkhead to the transmission housing.

What is claimed is: 
     
       1. In an automatic transmission of the type having a transmission housing, an input shaft rotatably supported in the transmission housing, an output shaft rotatably supported in the transmission housing, a planetary gear assembly coupling the input shaft to the output shaft, a clutch assembly operable to selectively engage the planetary gear assembly for driving the output shaft at a drive ratio, the improvement comprising a thrust bulkhead secured to the transmission housing and extending radially inwardly therefrom, a first thrust bearing assembly operably disposed between the planetary gear assembly and the thrust bulkhead such that an axial thrust load generated by the planetary gear assembly is transmitted through the first thrust bearing assembly to the thrust bulkhead, a second thrust bearing assembly operably disposed between the thrust bulkhead and the clutch assembly, and a clearance being provided between the thrust bulkhead and the second thrust bearing assembly such that the thrust bulkhead engages the second thrust bearing assembly only when the axial thrust load generated by the planetary gear assembly exceeds a given load. 
     
     
       2. The automatic transmission of claim 1 wherein the first thrust bearing assembly engages a first annular bearing surface formed on a first face of the thrust bulkhead. 
     
     
       3. The automatic transmission of claim 1 wherein the clutch assembly includes a clutch hub extending between the planetary gear assembly and the thrust bulkhead, the first thrust bearing assembly being interdisposed between the clutch hub and the thrust bulkhead, and a third thrust bearing assembly being interdisposed between the planetary gear assembly and the clutch hub. 
     
     
       4. The automatic transmission of claim 3 further comprising an intermediate race portion extending from the clutch hub and engaging the first thrust bearing assembly. 
     
     
       5. The automatic transmission of claim 1 wherein the clutch assembly further comprises a clutch mechanism disposed within an annular groove formed in the thrust bulkhead and operable to selectively couple the planetary gear assembly to the thrust bulkhead. 
     
     
       6. The automatic transmission of claim 5 wherein the thrust bulkhead has a hydraulic fluid passageway formed therein to provide fluid communication between a hydraulic pump assembly and the clutch mechanism for actuation thereof. 
     
     
       7. The automatic transmission of claim 1 wherein the second thrust bearing assembly is engageable with a second annular bearing surface formed on a second face of the thrust bulkhead opposite the first face. 
     
     
       8. The automatic transmission of claim 1 further comprising an intermediate race portion interdisposed between the second thrust bearing assembly and the thrust bulkhead. 
     
     
       9. The automatic transmission of claim 1 wherein the transmission housing has a first groove formed therein for receiving a first retainer and a second groove formed therein for receiving a second retainer, said thrust bulkhead being axially aligned and secured within the transmission housing by the first and second retainers. 
     
     
       10. The automatic transmission of claim 9 wherein the first groove has a radially tapered surface and the first retainer has a radially tapered face which cooperates with the radially tapered surface to axially bias the thrust bulkhead toward the second retainer. 
     
     
       11. A vehicular automatic transmission comprising: a transmission housing;   an input shaft rotatably supported in the transmission housing;   an output shaft rotatably supported in the transmission housing;   a planetary gear assembly selectively coupled between the input shaft and the output shaft;   a clutch assembly having a first clutch hub driven by the input shaft and operable to selectively engage the planetary gear assembly for driving the output shaft at a drive ratio;   a first thrust bearing assembly operably disposed between the planetary gear assembly and the first clutch hub such that an axial thrust load generated by the planetary gear assembly is transmitted through the first thrust bearing assembly to the first clutch hub;   a thrust bulkhead secured to the transmission housing and extending radially inwardly therefrom;   a second thrust bearing assembly operably disposed between the first clutch hub and a first annular surface being formed on a first face of the thrust bulkhead such that the axial thrust load generated by the planetary gear assembly is transmitted through the clutch hub to the thrust bulkhead;   a third thrust bearing assembly operably disposed between a second annular bearing surface formed on a second face of the thrust bulkhead opposite the first face and a second clutch hub operably coupled to the first clutch hub, a clearance being provided between the second annular bearing surface and the third thrust bearing assembly such that the thrust bulkhead engages the third thrust bearing assembly only when the axial thrust load generated by the planetary gear assembly exceeds a given load.   
     
     
       12. The automatic transmission of claim 11 wherein the transmission housing has a first groove formed therein for receiving a first retainer and a second groove formed therein for receiving a second retainer, said thrust bulkhead being axially aligned within and secured to the transmission housing by the first and second retainers. 
     
     
       13. The automatic transmission of claim 12 wherein the first groove has a radially tapered surface and the first retainer has a radially tapered face which cooperates with the radially tapered surface to axially bias the thrust bulkhead toward the second retainer. 
     
     
       14. The automatic transmission of claim 11 wherein the clutch assembly further comprises a clutch mechanism disposed within an annular groove formed in the thrust bulkhead and operable to selectively couple the first clutch hub to the thrust bulkhead. 
     
     
       15. An vehicular automatic transmission comprising: a transmission housing having a first annular groove and a second annular groove formed therein;   an input shaft rotatably supported in the transmission housing;   an output shaft rotatably supported in the transmission housing;   a planetary gear assembly selectively coupled between the input shaft and the output shaft;   a clutch assembly including a first clutch hub and a second clutch hub operably coupled to the first clutch hub, the clutch assembly operable to selectively engage the planetary gear assembly for driving the output shaft at a drive ratio;   a first thrust bearing assembly operably disposed between the planetary gear assembly and the first clutch hub such that an axial thrust load generated by the planetary gear assembly is transmitted through the first thrust bearing assembly to the first clutch hub;   a clutch retainer assembly including a thrust bulkhead extending radially inwardly between the first clutch hub and the second clutch hub, a first retainer disposed in the first groove and a second retainer disposed in the second groove, said first and second retainers axially aligning and fixedly securing the thrust bulkhead within the transmission housing;   a second thrust bearing assembly operably disposed between the first clutch hub and a first annular bearing surface formed on a first face of the thrust bulkhead such that the axial thrust load generated by the planetary gear assembly is transmitted through the first clutch hub to the thrust bulkhead;   a third thrust bearing assembly operably disposed between a second annular bearing surface formed on a second face of the thrust bulkhead opposite the first face and a second clutch hub, a clearance being provided between the second annular bearing surface and the third thrust bearing assembly such that the thrust bulkhead engages the third thrust bearing assembly only when the axial thrust load generated by the planetary gear assembly exceeds a given load.   
     
     
       16. The automatic transmission of claim 15 wherein the clutch assembly further comprises a first clutch mechanism disposed within a first annular groove formed in the thrust bulkhead, the first clutch mechanism being operable to selectively couple the first clutch hub to the thrust bulkhead. 
     
     
       17. The automatic transmission of claim 16 wherein the clutch assembly further comprises a second clutch mechanism disposed within a second annular groove formed in the thrust bulkhead, the second clutch mechanism being operable to selectively couple a member of the planetary gear assembly to the transmission housing.